1851 January 24: born Heworth, Co. Durham (England); educated at St. Michael's, Tenbury, and Magdalen College School, Oxford.
1873: elected to a Fellowship at Corpus, Oxford, under the old Statutes which stipulated celibacy as a condition of tenure. He lived in college continuously for fifty-eight years.
1875–1883: held a Lectureship in Modern History at Oxford; he was also Chaplain at college.
1884: "Conversion of Loegaire and his Death" published in Revue Celtique.
1885: revised text of Fortescue's Governance of England published; also "Notes on the Stowe Missal" in Zeitschrift für vergleichende Sprachforschung.
1887: a volume of reprints about Elizabethan Oxford, an early volume of the Oxford Historical Society.
1891–1898: acted as College Dean.
1892–1899: with Professor Earle worked on revising Two Saxon Chronicles.
1896: published an edition of Bede's Historia Ecclesiastica Gentis Anglorum.
1901: delivered Ford Lectures on the subject of King Alfred, published in 1902 as Life and Times of Alfred the Great.
1902: turned his interest to Celtic studies, particularly the lives of the Irish saints.
1905: two critical studies "Some new light on the Brendan legend" and "On two collections of Latin lives of Irish saints in the Bodleian Library" published in Zeitschrift für Celtische Philologie.
1908: published edition of Cáin Eimíne Báin in Ériu.
1910: the edition of the Irish Betha Farannáin appeared in Anecdota from Irish MSS., followed by a major work, the Vitae Sanctorum Hiberniae in two volumes.
1914: Latin lives of the saints Vie et Miracles de S. Laurent, Archevêque de Dublin published in Analecta Bollandiana; also this year appeared the Irish text with translation of the "Miracles of Senan" in Zeitschrift für Celtische Philologie.
1922: Bethada Náem nÉrenn: Lives of the Irish Saints published.
1923: "On the meaning of Ogam stones" appeared in Revue Celtique.
1925: three saints' lives published as Miscellanea Hagiographica to which was appended A Tentative Catalogue of Irish Hagiography; also published Irish Litanies (Henry Bradshaw Soc.)
1927 September 1927: died; "On the fragmentary state of the text of the Brehon Laws" published in Zeitschrift für Celtische Philologie.

Sources: P.S. Allen, F.M. Stenton, R.I. Best: Charles Plummer, Proceedings of the British Academy (1929), 463–474. These notes are followed by a bibliography of Plummer's works, pp.474–476.